Hello
I'm trying to synthesise CCTO using the molten salt approach. The reactants used are CaO, CuO and TiO2. The salts I've tried so far were KCl and KBr (3x weight of reactants). First I grind the reactants in agate mortar, then I add the salt and mill the mixture using ZrO2 ball mill with ZrO2 balls in methanol for 4h. After milling and drying the mixture is placed in corundum crucible and calcinated in 800oC for 5 hours. After calcination the powder is sintered, gray-ish black inside and white/a bit green-ish on the outside, where it had access to air. After grinding and XRD examination there's no sign of CaCu3Ti4O12 phase. I would be greatful for any advice regarding this particular problem and molten salt synthesis in general.
Thanks in advance
May be re-calcination required. Also optimize calcination temperature from 700-900 and calcination time from 3 hrs to 10 hrs.
Thanks for advice! Some additional informations: I've opened the crucible after 2h in 800C and the sample was already sintered, I was ecpecting to see the melt in there, was I right? Is it possible that methanol is not the right milling medium for this process? Maybe the amnount of salt is not sufficient? The mass of reactants is 0,0527g CaO, 0,2241g CuO, 0,3g TiO2, 1,7304g KCl.
You maintain proper stoichiometric ratio among the reactant, cacination, sintering temperature, detention time.
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